My Z gets stuck on ~150mm for no clear reason. Max height should be 160mm, but when it hits that certain point, it won't move up or down anymore. If I tell bed to go up and same time help the lead screw by turning it gently, it starts to move again.

I haven't actually printed anything that tall, I did just test it to make sure what actual height limit is.

Two stepper drivers were adjusted to 0.87v and two to 1.13v. I guess motors are the same model, so I did adjust them all to ~1.1v. This didn't help the Z problem. The drivers are not labeled, so I'm not sure which is for which motor.

It is hard to measure, but I think leadscrew is tilted less than millimeter to left. This makes it too tight bed to go all the way down I cannot see a way to tilt it back, construction is too solid.

I did try to loosen various screws and loosening the part that connects bed to lead screw did help a little bit. Now it gets stuck ~158mm and I think I can safely print up to 155mm which is close enough. I did set Cura to 150mm height and only increase it if absolutely necessary.

But I still think this should have been noticed in quality check. You did print a square with this very printer, but didn't bother to check Z height?